A large and growing number of the residents of the United States speak English as a second language. Opportunities for employment, promotion, and education for this population can be negatively affected by their inability to communicate effectively in English. Little is known, however, about the specific phonetic and phonological factors which affect the intelligibility of non-native speech. This project proposes to investigate the effects on intelligibility of the phonetic and phonological characteristics of two types of foreign-accented English (native Chinese and Spanish speakers). This research will provide the empirical basis for the development of a computer-based pronunciation training system which will utilize both speaker-dependent and speaker- independent automatic speech recognition technology. Unlike other efforts to develop computer-based speech trainers, this system will provide, as feedback, a measure of speech quality which has been shown to correlate well with human judgements. To establish the validity' of utilizing speech-recognition technology for second-language pronunciation training the capability of the speech recognizer to' perform the relevant acoustic discriminations will be assessed. The effectiveness of the computer-based speech training aid will then be evaluated through pre- and post-training intelligibility testing of non-native speech.